Emanuele Biggi

Blog: Pound signs in your eyes? Why that’s not appropriate for measuring conservation impact.

Posted: 19th October, 2021

Recent criticism that zoos can’t claim to be effective conservation organisations, because the reported amounts of money spent in the field are too small, highlights common misconceptions and a lack of understanding around how conservation works on the ground and how conservation impact should more accurately be measured. But how can we be sure conservation is working? How do we measure success?

Conservation impacts are improvements in the status of wildlife populations and ecosystems, as well as the communities that live alongside them. The magnitude of these impacts is not necessarily related to the cost of the conservation activities undertaken. Instead, impact can be measured in several ways.

Some zoos and aquariums, such as Bristol Zoological Society, assess the impact of their conservation work through a strategy or a masterplan, with wildlife and community-based objectives for each conservation programme that are monitored continuously to determine success. For example, a key objective for their current North-western Madagascar Conservation Programme was to determine best practice for reforestation in the harsh climate of the Sambirano region, after previous methods had failed. This involved testing and monitoring tree planting methods experimentally; the most effective method has now been determined and next year will be rolled out across the protected area. In other projects, the impact might be clearly seen and recorded in the target wild species, using measures such as the IUCN Red List to assess and identify changes in the stability of wild populations. Durrell Wildlife Conservation Trust have taken use of the Red List criteria a step further, determining how a population or species might have fared without their intervention, for example, the pink pigeon and echo parakeet from Mauritius (Durrell Index, Young et al., 2014). This approach has now been developed and expanded into a global framework for assessing species recovery and conservation success; the IUCN Green Status of Species (Akcakaya et al. 2018).

Chair of the IUCN Species Survival Commission, Jon Paul Rodriguez, says, “one of the key strengths of conservation-focused zoos and other ex-situ organisations is the breadth of skills and knowledge that they can contribute to addressing conservation issues, meaning their conservation impact often extends far beyond their direct field work”. As an example, vast amounts of research is carried out at zoos and aquariums, often having a significant conservation impact that is not clearly reflected by financial investment (e.g., Welden et al. 2020: 3,345 peer-reviewed articles published by EAZA zoos between 1998-2018). Recently for example, Crocodiles of the World participated in research to develop a process of detecting environmental DNA, genetic material left behind by animals in their environment. This work will be used to develop more resource-effective surveys for Siamese crocodiles in Cambodia, an essential part of their protection. Colchester and Twycross zoos have contributed similarly in tests for eDNA samples for great apes, helping develop techniques to monitor wild populations. Wildlife vets regularly use knowledge gained from zoo animals to develop techniques to support the health of wild animals, for example the field anaesthesia machine developed by the late John Lewis (Wildlife Vets International) now used to sedate tigers in the field.

Many zoos and aquariums also use their training and skills to build capacity within the applied conservation sector, with zoo/aquarium staff training colleagues both internationally (for example through staff or resource exchanges) and also within their own communities, through practical training courses and Higher Education programmes. Bristol Zoological Society currently runs six degree programmes with four university/college partners with many alumni who have gone on to impactful careers in conservation around the world.  The Zoological Society of London is a global leader in SMART (Spatial Monitoring and Reporting Tool) training, directly supporting ranger training in more than 20 sites.  SMART has been implemented in 10 ZSL sites across Asia covering an area of over 12,000 km2 and a further 10 in Africa, covering almost 20,000 km2 (ZSL 2021). Durrell Wildlife Conservation Trust recently led the development of the IUCN Global Register of Competencies for Threatened Species Recovery Practitioners to enhance training, professionalism and skills capacity across the international conservation community.

An additional valuable (and yet hard to quantify) zoo and aquarium conservation impact can be seen in advocacy. Chester Zoo provides an example here in their work around sustainable palm oil; establishing the world’s first Sustainable Palm Oil City and encouraging other communities in sourcing all their palm oil from sustainable sources, supporting the long-term future of vast numbers of species (Ancrenaz et al, 2018).

One of the most obvious areas where zoos and aquariums can have impact is through the scientific management of wildlife populations under human care, i.e. ex situ conservation. In a recent study, Bolam et al. (2020) found that the conservation of nearly two thirds of the 45 bird and 29 mammal species likely saved from extinction involved ex situ conservation activities, many led by zoos, in addition to in situ action, policy and advocacy. Examples, include the Bali myna and pygmy hog which would likely have gone extinct in the wild within the last 20 years. Zoo-based conservationists participate further through their work for a vast number of IUCN committees, contributing to numerous species conservation action plans and many IUCN Red List, and new Green List, assessments. Participation in such activities, financially supported by their zoos, leads to direct conservation actions over the long term (Lees et al. 2021). Therefore, even if you choose money as your metric; focussing on just one aspect of conservation spend; i.e., how much is spent in situ, can also give a very skewed perspective.

Despite these various ways of achieving conservation impact, zoos, aquariums and other conservation organisations are often judged against only one measure of input – conservation spend in the field. The appeal of this metric is understandable; it is easier to communicate, simplifies comparisons across organisations and, in some instances, is easier to measure compared with some of the outcomes discussed above. However, conservation spend should be interpreted with extreme caution, and those falsely equating spend with impact should be called to account – no pun intended!

A significant challenge in the use of spend as a measure of impact, is that the cost of conservation varies dramatically from species to species, from place to place and according to the complexities of the work needed. In some cases (often in the case of larger species), conservation can be incredibly expensive; the cost of habitat protection and anti-poaching activities to conserve the Sumatran rhino at just four priority sites is estimated to be $1.2m USD per year (Zafir et al 2011). The cost to eradicate an island of invasive species can also be astronomical; e.g., Gough Island eradication of house mice to protect threatened seabird chicks was estimated at £7.6m (RSPB 2017). A compounding factor is that successful impact for many of the most highly threatened species may not be seen in the short term; (i.e. 0-5 years), but over a much longer time frame, even decades, often requiring some degree of permanent, ongoing management. In other cases though, the status of species at severe risk of extinction can be improved at much lower cost. Conservation of the Critically Endangered Desertas wolf spider near Madeira required controlling plants that outcompeted others on the island following the loss of grazers, leading to fewer burrows for breeding spiders. Habitat management collectively led by Bristol Zoo and the Madeiran Government has led to an increasing spider population for less than €30,000 since 2016 (G. McCabe pers. comm.). It should also be noted that restoring ecosystems can have cascading effects for other non-target species that share the habitat, further increasing impact from a relatively small spend.

So the criticism that zoos cannot claim to be effective conservation organisations because the reported amounts of money spent on field conservation are too small, not only demonstrates a poor understanding of conservation impact, it also propagates a dangerous viewpoint that grassroots conservation may not be effective because it does not involve spending enough money. This false narrative undermines the incredible and impactful work accomplished around the world by those, including zoos and aquariums, on the front lines of conservation with limited budgets.

In conclusion, we have all heard it before; money isn’t everything. Having said that, those of us involved in managing the conservation work of BIAZA zoos do feel that more can be done. We are living at a time of ecological and climate crisis, which will have devastating impacts for wildlife and people. Zoos and aquariums have an essential role in what must be a multi-pronged approach, and we must all step up to play an even greater role in field conservation initiatives, breeding and reintroduction activities, promoting pro-conservation behaviour change, and advocating for change at national and global levels. We would encourage those who are raising these concerns to instead join with us in maximising our collaborative efforts, working with colleagues around the world to generate success stories to celebrate and showcase to the world that it is possible to save wildlife and their habitats, together.

By BIAZA's Field Conservation Committee

All blogs reflect the views of their author and are not a reflection of BIAZA's positions. 


Akcakaya et al. (2018) Quantifying species recovery and conservation success to develop an IUCN Green List of Species. Conservation Biology 32 1128-1138

Ancrenaz, M., Barton, C., Riger, P. & Wich, S. et al. 2018. Building relationships: how zoos and other partners can contribute to the conservation of wild orangutans Pongo sppInternational Zoo Yearbook, 52, 1-9.

Bolam et al. (2020) How many bird and mammal extinctions has recent conservation action prevented? Conservation Letters https://doi.org/10.1111/conl.12762

Bristol Zoological Society (2018) Conservation Masterplan 2018-2022. https://bristolzoo.org.uk/zoo-information/about-us/accounts-reviews-and-plans

Lees, C.M., A .Rutschmanna, A.W. Santurea & J.R.Beggsa (2021) Science-based, stakeholder-inclusive and participatory conservation planning helps reverse the decline of threatened species. Biological Conservation 260: 109194

RSPB (2017) Island Restoration News: Gough and Henderson. Issue 1, March 2017. https://cd5d69b9-df2f-4bb3-93d3-33803041c3b7.filesusr.com/ugd/f76e15_ee4ad52d4f914240b65541121153d808.pdf

Young et al. (2014) Accounting for conservation: Using the IUCN Red List Index to evaluate the impact of a conservation organization. Biological Conservation http://dx.doi.org/10.1016/j.biocon.2014.09.039

Zafir et al. (2011) Now or never: what will it take to save the Sumatran rhinoceros Dicerorhinus sumatrensis from extinction. Oryx 45 225-233.

Welden, H.L.A., Stelvig, M., Nielsen, C. K., Purcell, C., Eckley, L., Frost Bertelsen, M. & Hvilsom, C. (2020). The contributions of EAZA zoos and aquariums to peer-reviewed scientific research. Journal of Zoo and Aquarium Research, 8: 133–138. https://doi.org/10.19227/jzar.v8i2.486

ZSL (2020) Implementing the SMART approach. ZSL website. https://www.zsl.org/conservation/how-we-work/conservation-technology/implementing-the-smart-approach

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